title: Effect of nitric oxide on anterior segment physiology in monkeys.
abstract: OBJECTIVE
  To determine the effect of the nitric oxide donor, sodium nitroprusside (SNP), and the nitric oxide synthase (NOS) inhibitor, L-nitro-arginine-methylester (L-NAME), on IOP, mean arterial pressure (MAP), pupil diameter (PD), refraction (Rfx), aqueous humor formation (AHF), and outflow facility (OF) in monkeys.
  
  
  METHODS
  Monkeys were treated with single or multiple topical treatments of 500 μg SNP or L-NAME to one eye. IOP was determined by Goldmann applanation tonometry, PD with vernier calipers in room light, Rfx by Hartinger coincidence refractometry, AHF by fluorophotometry, and MAP with a blood pressure monitor. OF was determined by two-level constant pressure perfusion following anterior chamber exchange.
  
  
  RESULTS
  Following four topical treatments with 500 μg SNP, 30 minutes apart, IOP was significantly decreased from 2 to 6 hours compared with the contralateral control with the maximum IOP reduction of 20% at 3 hours (P < 0.001). PD, Rfx, and AHF were unchanged. Effects on MAP were variable. OF after SNP exchange was significantly increased by 77% (P < 0.05) at 10(-3) M. Topical L-NAME had no effect on IOP, PD, Rfx, or MAP.
  
  
  CONCLUSIONS
  Enhancement of nitric oxide concentration at targeted tissues in the anterior segment may be a useful approach for IOP reduction for glaucoma therapy. Additional studies are warranted before conclusions can be made regarding the effect of NOS inhibition on ocular physiology in nonhuman primates.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, USA.
authors.forename: Galen W
authors.initials: GW
authors.lastname: Heyne
authors.forename: Julie A
authors.initials: JA
authors.lastname: Kiland
authors.forename: Paul L
authors.initials: PL
authors.lastname: Kaufman
authors.forename: B'Ann T
authors.initials: BT
authors.lastname: Gabelt
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000869:Anterior Eye Segment / Q000187:drug effects* / Q000502:physiology; D001082:Aqueous Humor / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D007429:Intraocular Pressure / Q000187:drug effects; D008252:Macaca fascicularis / Q000502:physiology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology*; D011680:Pupil / Q000187:drug effects; D012029:Refraction, Ocular / Q000187:drug effects
chemical_list: D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D009599:Nitroprusside; D009569:Nitric Oxide; D019331:NG-Nitroarginine Methyl Ester
keywords: intraocular pressure; nitric oxide; outflow facility